At the present time, the most prominent method for the catalytic oxidation of organic waste water is in a waterfilled basin media. Various modifications of this method have been made from time to time, with the object being to shorten the period of bringing the process elements together (microorganisms/waste materials/oxygen) and improving the environment in which they all perform. Most of such modifications have been classed as dipping filter beds or contact media in such forms as corrugated or flat plates 93 (FIG. 1) in basin 45, or rotating biological contactors 97 (FIG. 2) in basin 45. These contactors rotate with the lower half in the waste water and the upper half in the air. Although these media do remove and hold one or more of the process elements from the fluid, they do it by a contact action rather than a filtering action which connotes passing the fluid through the media in order to separate or remove the particles. Accordingly, the term media will be used in subsequent discussions unless a filtering action is actually performed. One of the important aspects in this type of system is to avoid impeding the flow of the process and the aeration. To this end, the contact media material is oriented in both the vertical and longitudinal flow directions so that its surface contact area is in a plane parallel to the flow and it is also spaced sufficiently far apart to permit free flow of the waste materials and air between the members. This results in a system wherein the contact media material forms a relatively small percentage of the volume of the water basin.
A more recent contact media design uses a large number of ribbon-like contact members consisting of a synthetic fiber, with the fibers having a large number of fluffs or loops projecting therefrom. This system, indicated at 91 in FIG. 1, extends the ribbon-like contact members in a vertical direction. In one particular usage the ribbons are extended between upper and lower frame members so as to create a sinusoidal line of ribbons as they move to successive frames, with the sinusoidal lines lying in a plane. As with other contact media, this arrangement of sinusoidal ribbons forms a vertical plane parallel to the flow path of the process and air which is spaced sufficiently far apart from adjacent sinusoidal lines to permit the free flow of the waste material and air. As will be obvious, the total amount of the ribbons consumes a small percentage of the volume of the water basin.
The basic function of these types of contact media is to provide a surface to which the microorganisms can attach and then catch the random wandering waste material and air so that the biodegradation process can be accomplished in the shortest possible time and to the fullest extent possible.
Although each of the above-discussed installations has achieved a certain level of success, there are disadvantages in each of them which results in the fact that they do not provide the optimum level desired. Such disadvantages will be discussed below.
The installation, which contains the plane of the contact media parallel to the flow of the process, provides only a brushing, bumping, bouncing contact of the waste material and air, with no positive entrapping action.
Additionally, the spacing between the planes of the contact media and the small volume in relation to the total volume of the basin results in the contact media interacting with only a relatively small percentage of the random wandering process elements and only those directly adjacent to the media. A large percentage of the biodegradation continues to be conducted in the fluid.
Although these systems are designated as filter beds, the fact is that little filtering action is accomplished as the process moves from the influent to the water basin to its exit.
Accordingly, it is the object of the present invention to provide an apparatus which is a true filter bed/pad which will hold the microorganisms and entrap all of the waste material, together with the necessary air/oxygen and/or other process elements, and where a favorable environment is formed in which total biodegradation can be accomplished on all the waste material.